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Review: Convert (PBF) vs. ConvertBot for iPhone

Who would win a fight: a robot or a polar bear? Since we won't be finding …

To say unit converters are the new tip calculators of the App Store wouldn't be that far from the truth. There have been many entries into this category—far too many to do a comparison review of them all—so we decided to pit two of the newer entries against one another: Convert from Polar Bear Farm and ConvertBot from TapBots.

Right away, if we were to compare these two applications based purely on the beauty and polish of the applications' interfaces, ConvertBot would win hands-down. TapBot continues its "robot" metaphor (which was started with WeightBot), giving you the illusion that you are interacting with a robot. Convert, while attractive, does suffer from quite possibly the worst textual logo I've seen in quite some time—your eye is immediately drawn to it, and it takes away from the overall look of the application.

In addition to the near-genius marketing angle of a stable of robots, one thing TapBots has done extremely well is to make its applications fun to use. It may not sound like much, but once you realize that their first app was a weight tracker, the feat becomes a little more astounding. ConvertBot isn't as fun to use as WeightBot, but it does take unit conversion—an otherwise menial task—and add some flair.

The two applications offer many of the same categories and measurements, but in the end, Convert beats ConvertBot out in sheer numbers. While ConvertBot has only 10 currencies, Convert has seemingly every currency in the world short of livestock. Both applications automatically update exchange rates. Convert also has a Typography section, which allows a user to convert units such as inches to points or picas, but it lacks the "Work" category of ConvertBot that lets you convert joules, calories, and the like. Depending upon your needs, your mileage may vary. The other differences are minor, with Convert having one or two more units here and there, but nothing in the way of essential units.

While Convert offers more units for conversion, one major UI omission makes the large number somewhat daunting. In ConvertBot, you have the abbreviated unit in the selection area, but above, you get the whole, unabbreviated name. In Convert, if you don't know what currency IDR is, for example, you will need to exit the application and look it up. This is obviously not convenient.

Additionally, the lack of a negative button on the number pad input is a poor omission; the solution for entering negative numbers is to enter the positive counterpart then tap the number with your finger. This solution is obscure and one I wouldn't have found without the help of the developer. At the same time, the size of the number pad is appreciated in Convert.

ConvertBot is attractive, though some may argue that it is over-designed and that the interface sacrifices usability and speed for cool factor. There are some places where certain actions feel forced, but once you get used to them, it really isn't so bad. The problem is that, if you want to do many conversions of different units one right after another, speed is limited by the UI. Where Convert has lists, ConvertBot has a wheel. Where you can change to units of the same group in the input screen in Convert, you have to back out to the unit selection screen in ConvertBot. For hardcore users who do a lot of conversions, the added UI of ConvertBot will be annoying, but for the casual user, the UI is a bit fun.

ConvertBot really shines in its ability to translate from one unit to a measure of a unit plus a smaller measure of a unit. For instance, the user can calculate inches into feet and inches; instead of getting 4.5 feet for 54 inches, the application can display four feet, six inches.

At this point, both applications have bugs. ConvertBot is currently having issues with the use of a decimal as a comma for foreign users, and Convert isn't recalculating negative numbers until a new number is added. Both companies have fixes already submitted to the App Store, which is a good omen for future updates and releases.

In short: for casual use, check out ConvertBot. For serious use, check out Convert.

10 Reader Comments

How many unit converters are available? Is the number really so prohibitively high that you can't do some kind of comparison review? That article would be quite compelling, while this one is only moderately interesting.

I prefer to have iPhone unit converters built into good calculators. You often need to do more than just convert A to B. I'm using PCalc but I would like the author to add some more oddball conversions (e.g. doesn't have micrometers or mils).

"ConvertBot, while attractive, does suffer from quite possibly the worst textual logo I've seen in quite some time—your eye is immediately drawn to it, and it takes away from the overall look of the application. "

I think the textual logo belongs to Convert by Polar Bear Farms. Especially since that is what the logo says. So I think the initial confusion is that the app icons at the top are reversed as well. Left should be "CovertBot" while right should be "Convert"

Originally posted by mrcollins:I think you've got this line backwards:

"ConvertBot, while attractive, does suffer from quite possibly the worst textual logo I've seen in quite some time—your eye is immediately drawn to it, and it takes away from the overall look of the application. "

I think the textual logo belongs to Convert by Polar Bear Farms. Especially since that is what the logo says. So I think the initial confusion is that the app icons at the top are reversed as well. Left should be "CovertBot" while right should be "Convert"

You are correct. I have no idea how that happened. The error has been fixed on the server and should be live in a few minutes.

The text logo is a slightly deeper issue than just the fact that it's ugly and distracting: screen space on an iphone is precious. From the user's perspective, no reason to have the name of the app, let alone the developer, on the screen at all times. This can only be good for maketers and lawyers. Personally, I consider this a design defect in the program.

Originally posted by hderycke:The text logo is a slightly deeper issue than just the fact that it's ugly and distracting: screen space on an iphone is precious. From the user's perspective, no reason to have the name of the app, let alone the developer, on the screen at all times. This can only be good for maketers and lawyers. Personally, I consider this a design defect in the program.

Design defect? What should I have put there instead? A fart button? :\

In all seriousness, the name of the app is there so that users associate the app, the icon, the style, and the name all together. Reinforcement. Helps users remember what they've used if they want to come back to it. From a designer's perspective, Convert has everything you need to do conversions without changing most of the UI as you make all your selections. Tap what you want to change, change it, continue. In Convert there aren't any "okay" or "accept" buttons. The UI is simple, and very much to the point.